Claw for a milking machine

ABSTRACT

A claw for a milking machine comprises a housing (1, 3) defining an inner space and having four inlet members (8&#39;, 9&#39;), which are intended to connect the inner space of the housing (1, 3) to a respective teatcup of the milking machine, and an outlet member, adapted to connect the inner space of the housing (1, 3) to a milk collecting member of the milking machine via a conduit member. The four inlet members are provided in pairs in such a manner that they are adapted to the natural position of the teats. Thereby, a first pair (8), intended for two front teats of the animal to be milked, has a different position with respect to the center axis (5) than a second pair (9&#39;), intended for the rear teats of the animal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention refers to a claw for a milking machine, comprisinga housing having four inlet members, which via four teatcup liners areadapted to connect the housing to four respective teats of an animal tobe milked, and an outlet member, which via a conduit member is adaptedto connect the housing to a milk collecting member of the milkingmachine, said housing having a center axis extending through the clawessentially vertically when the claw, in an operating position, isattached to the udder of the animal, said four inlet members beingdistributed around the centre axis and provided in pairs in such amanner that they are adapted to the natural position of the teats of theudder of the animal, a first pair of the inlet members, which isintended for two front teats of the animal, being directed obliquelyforwardly and outwardly and having a different position with respect tothe centre axis than a second pair of the inlet members, which isintended for the rear teats of the animal and is directed obliquelyrearwardly and outwardly with respect to the centre axis.

2. Description of the Prior Art

Such a claw is known by EP-B-418 260 and comprises a housing, having acenter axis which in an operating position of the claw extendsvertically, an upper portion and a lower portion. The inner space of thehousing forms a chamber for receiving milk via four inlet membersconnected to a respective teatcup of the milking machine via a shortmilk conduit. An outlet member, which via a milk conduit is connected toa milk collecting unit of the milking machine, extends from saidchamber. Both the outlet member and the inlet members are fixedlyprovided on the upper portion of the housing and are thus not movable inrelation to each other. The outlet member comprises an outlet nippleextending radially outwardly perpendicularly from the center axis of thehousing. The inlet members comprise four inlet openings provided inpairs so that one of the pairs is intended to be connected to teatcupsbeing applied to the front teats of the cow and the other pair isintended for teatcups being applied to the rear teats of the cow. Theinlet members are provided on a conical surface of the upper portion atthe same height with respect to the vertical center axis.

By studying the position of the teats of the udder of cows, it has beenrecognized that the distance between the two front teats is longer thanthe distance between the two rear teats. An investigation from 1983discloses an average distance between the front teats of 150 mm, betweenthe rear teats of 85 mm and between the rear and front teats of 100 mm.Furthermore, it has been recognized that the front udder half is higherthan the rear one, i.e. the two front teats are located at a higherposition than the two rear teats. When the udders are charged with milkthe teats are relatively stiff and straggling and will therefore berelatively immovable in relation to these positions. This situationmakes it difficult to attach teatcups configured in a conventionalmanner to the teats of the cow, since the teatcups do not reach theteats properly and it may therefore be difficult to attach teatcups insuch a manner that they close tightly against the teat. If the teatcupliner does not close tightly against the teat, there may be asignificant air inlet between the teatcup liner and the teat, which maynot be controlled. This deficiency makes the milking less effective andrequires a higher capacity of the vacuum pump and it may in certainsituations lead to detachment of the teatcups before the milking hasbeen terminated. The milk conduits may also not be arbitrarily long,since the claw in such a case will touch the ground or the floor, atleast during the end of the milking. The problems mentioned above havebecome worse in recent time, since the short milk conduit has becomethicker and thus stiffer in order to be able to conduct an increasingmilk flow. Furthermore, it has been difficult to provide a closeconnection between the short milk conduit and the housing of the clawdue to the bending forces acting on the milk conduit. Because of this,air tends to penetrate the inner space of the housing between the shortmilk conduit and the inlet opening.

SE-B-449 154 discloses a milking machine having a claw comprising ahousing with an upper portion and a lower portion. Four inlet nipplesare provided on the upper portion and connect the inner space of thehousing to a respective teatcup of the milking machine via conduits.Four outlet nipples are provided on the lower portion and connect theinner space of the housing to a milking collecting member of the milkingmachine via conduits. In the inner space of the housing there are fourintermediate walls dividing the inner space of the housing in fourchambers of equal size. One inlet nipple and one outlet nipple is inconnection with each chamber. The upper portion may be rotated in fixed90°0 steps in relation to the lower portion so that each inlet nipplemay be displaced to be opposite another outlet nipple.

U.S. Pat. No. 2,775,225 and U.S. Pat. No. 2,429,983 both disclose a clawprovided with four inlet nipples provided in pairs and adapted to theposition of the teats of the udder. These documents do not teach how toconfigure a passage through the wall of the claw in order to be able toreceive a teatcup liner.

FR-A-1 158 460 discloses a quite different type of claw having fourinlet nipples, all directed in essentially the same direction. Eachnipple is mounted in a passage extending through an essentially planewall portion of the claw. The teatcup liners are adapted to be mountedon the nipples in a conventional manner.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the problemsmentioned above and provide a claw having such a configuration that itmay be attached in a secure and tight manner to the teats of an animalto be milked.

This object is obtained by the claw initially defined and characterizedin that each inlet member comprises a passage extending through the wallof the housing and arranged to receive one of said teatcup linerstherethrough, that each passage is surrounded by and extends through aportion of the wall of the housing, and that this portion hasessentially plane parallel surfaces. By such a claw configurationadapted to the animal it is ensured that the teatcups in a better waythan previously reach their respective teats and thus that theengagement or the grip between the teatcup liners and their respectiveteats is improved. Furthermore, the tensions in the milk conduitsdecrease and the claw will be suspended in more natural manner beneaththe animal. Furthermore, such a configuration results in an equal,downwardly directed force, acting at each teat, for all four teats andthereby an equal and proper milk extraction of each teat is guaranteed.Since the portion through which the passage extends has essentiallyplane parallel surfaces the mounting of the milk conduits in the housingof the claw is facilitated and one may prevent air from penetrating thehousing, thereby generating disturbing noise. Furthermore, it is therebypossible to keep the required capacity of the vacuum pump on a lowerlevel than otherwise would have been the case.

According to an embodiment of the invention, the inlet members areprovided in pairs in such a manner that the first pair is located at ahigher position with respect to the center axis than the second pair. Innormal cases the front teats of a cow are located at a higher positionthan the rear teats. By this embodiment it is possible to compensate forthis fact in such a manner that the downwardly directed force at eachteat is equal and that center axis of the claw will extend verticallyduring the milking. This vertical operating position of the claw isadvantageous since the milk collected in the inner space of the claw maybe transported away therefrom in an uniform and continuous flow.

According to a further embodiment of the invention, the inlet membersare provided in pairs in such a manner that the distance between theinlet members of the first pair is greater than the correspondingdistance of the second pair. In this way, one takes into account thefact that the front teats of the cow in the normal cases have a greatermutual distance than the rear teats of the cow.

According to a further embodiment of the invention, each passage extendsin a direction which essentially forms a normal to the associatedportion. Furthermore, the inlet members may be provided in pairs in sucha manner that the passages of the first pair extend obliquely forwardlyand outwardly by a first angle in relation to a horizontal plane towhich the center axis forms the normal and the passages of the secondpair extend obliquely rearwardly and outwardly by a second angle inrelation to the horizontal plane. Furthermore, each inlet member mayextend in a direction directed essentially straight towards the teatassociated with the inlet member when the claw in an operating positionis attached to the udder of the animal. Also in this way, it is possibleto compensate for the fact that the front teats of the cow are locatedat a higher position than the rear teats. Furthermore, it is possible tocompensate for the fact that the front teats of the cow in normal caseshave a longer mutual distance than the rear teats of the cow.

According to a further embodiment of the invention, the housingcomprises a first portion and a second portion, the outlet member isprovided on the first portion, the inlet member is provided on thesecond portion and the first portion is rotatable in relation to thesecond portion. By such a configuration the outlet member may bedisplaced in relation to the inlet members so that it is directedtowards the milk collecting member of the milking machine, i.e. theconduit member provided between the outlet member and the milkingmachine will not apply any torsional force to the claw but the lattermay maintain an optimal operating position in relation to the teats ofthe animal. Furthermore, such a configuration is advantageous since theclaw according to the invention has a pronounced front and rear end.Thereby, the conduit member may be adjusted in such a manner that it isdirected essentially forwardly if the milking machine is located infront of the animal to be milked, laterally if the milking machine islocated laterally of the animal to be milked, or rearwardly if themilking machine is located behind the animal to be milked.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be explained more closely by means ofdifferent embodiments, shown by way of example, and with reference tothe drawings attached.

FIG. 1 discloses a vertical section through a claw according to a firstembodiment of the invention.

FIG. 2 discloses a view from above of a portion of the claw according toFIG. 1.

FIG. 3 discloses a section along the line III--III in FIG. 2.

FIG. 4 discloses a partly sectional view from above of another portionof the claw according to FIG. 1.

FIG. 5 discloses a vertical section through a claw according to a secondembodiment of the invention.

FIG. 6 discloses a view from above of a portion of the claw according tothe second embodiment.

FIG. 7 discloses a section along the line VII--VII in FIG. 6.

FIG. 8 discloses a side-view of an animal during milking by a clawaccording to the invention.

FIG. 9 discloses a view from behind of an animal during milking by aclaw according to the invention.

DETAILED DESCRIPTION OF DIFFERENT EMBODIMENTS

With reference to FIG. 1 to 7, a claw according to the invention isdisclosed, which comprises a housing 1. The housing 1 comprises a firstupper portion 2, a second intermediate portion 3 and a third lowerportion 4. Through the housing 1, a center axis 5 extends essentiallyvertically when the claw is in an optimal operating position. On theupper portion 2 an outlet member is provided, which in the exampledisclosed comprises an outlet nipple 6 extending essentially radiallyoutwardly from the housing 1 and the upper portion 2 with respect to thecenter axis 5, i.e. the outlet nipple 6 has a longitudinal center axis 7being perpendicular to the center axis 5. On the intermediate portion 3four inlet members, shown as inlet nipples 8, 9 inlet passages and 8',9', respectively, are provided.

Components which in the different embodiments have correspondingfunctions have been given the same reference signs.

According to the embodiments disclosed in FIG. 1-3 the inlet memberscomprise four tubular elements extending obliquely upwardly andconfigured as inlet nipples 8, 9. Each inlet nipple 8, 9 is intended tobe connected to a short milk conduit (not disclosed) which in turn isconnected to a teatcup (not disclosed). The inlet nipples 8 are intendedfor the teatcups to be connected to two front teats of a cow to bemilked and the inlet nipples 9 are intended for the teatcups to beconnected to the rear teats of the cow. As is disclosed in FIG. 3, thefront inlet nipples 8 extend to a higher position with respect to ahorizontal plane 10 to which the center axis 5 forms the normal than therear inlet nipples 9. Since the inlet nipples 8 and 9 have an equallength, this configuration has been accomplished by providing the frontinlet nipples 8 at a higher location than the rear inlet nipples 9 onthe intermediate portion 3. The front inlet nipples 8 extend in alongitudinal direction obliquely forwardly and outwardly by an angle aof inclination in relation to the horizontal plane 10 and the rearoutlet nipples 9 extend in a longitudinal direction obliquely rearwardlyand outwardly by a angle b of inclination in relation to the horizontalplane 10. It should be noted that the angles a and b define theinclination of the longitudinal directions of the inlet nipples 8, 9 inthe two planes being radial with respect to the centre axis 5 andcoinciding with the section III--III in FIG. 2. As is disclosed in FIG.3, the angle a is greater than the angle b. Furthermore, as is disclosedin FIG. 2, the mutual distance c between the front inlet nipples 8 isgreater than the mutual distance d between the rear inlet nipples 9.

According to the embodiment disclosed in FIG. 5-7, each inlet membercomprises an inlet passage 8', 9' which extends through the wall of thehousing 1 and is adapted to receive a short milk conduit 11 fixed to thewall of the housing 1 by means of two ribs 11a, 11b, provided on theouter surface of the milk conduit 11 and extending therearound, see FIG.7. Each such short milk conduit 11, which practically frequently are aprolongation of a teatcup liner, is a standard product which preferablyis manufactured in one single length. In such a manner, themanufacturing of the short milk conduits/teatcup liners is facilitatedand exchange thereof is simplified since it is not necessary to takeinto account the positioning of an individual teatcup liner with respectto a particular inlet passage. The housing 1 disclosed in FIG. 5-7 formsa wall by means of which the inner space of the housing 1 is delimited.This wall has a wall portion 12 around each inlet passage 8', 9', i.e.the inlet passage 8', 9' extends through said portion. This wall portion12 is essentially plane parallel, i.e. the outer surface of the portion12 is essentially parallel with the inner surface of the portion 12, andthese surfaces are essentially plane. This means that the ribs 11 a and11b may sealingly close the passage, so that no air may penetrate theinner space of the housing 1 between the edge side of the inlet passage8', 9' and the milk conduit 11 introduced in the inlet passage 8', 9'.It should also be noted that each inlet passage 8', 9' extends in adirection essentially perpendicular through the wall portion 12, seeFIG. 7, i.e. the edge side of the passage 8', 9' is essentiallyperpendicular to the outer surface and the inner surface of the wallportion 12. Thereby, the sealing capacity of the milk conduit 11 againstthe housing around the passage 8', 9' is further improved. In the areasbetween the wall portions 12, the housing 1 may have an arbitrary shape.In a similar way as in the embodiment according to FIG. 1-3, the fourinlet passages 8', 9' are provided in pairs in such a manner that thefirst pair inlet passages 8', intended for two front teats of a cow tobe milked, is located at a higher position with respect to the verticalcenter axis 5 than a second pair of inlet passages 9', intended for therear teats of the cow, see FIG. 7. Furthermore, the four inlet passages8', 9' are arranged in such a manner that each inlet passage extends insaid direction through the wall of the housing 1 essentially straighttowards the teat to which the inlet passage 8', 9' is intended to beconnected. Furthermore, said direction of each passage 8', 9' coincideswith the normal to the portion of the wall of the housing 1, throughwhich the inlet passage 8', 9' extends, i.e. the plane parallel wallportion 12. This means that the wall portions 12 comprising theessentially plane parallel surfaces are not parallel to but are inclinedin relation to the horizontal plane 10 and that the normals of the wallportions 12, i.e. said directions, of the first pair 8' of the passages,which are intended for the two front teats of the cow to be milked,extend obliquely forwardly and outwardly by a first angle a in relationto the horizontal plane 10 and that the normals, i.e. said directions,of the second pair of inlet passages 9', which is intended for the rearteats of the cow, extend obliquely rearwardly and outwardly by a secondangle b in relation to the horizontal plane 10. It should be noted thatthe angles a and b define the inclination of the directions of the inletpassage 8', 9' in the two planes which coincide with the sectionsVII--VII in FIG. 6. The angles a and b in FIG. 7 are defined by theheight difference between the front and the rear teats of the cow, i.e.the fact that the rear teats normally are located at a lower position,by the distance between the front and the rear teats and by the mutualdistance between the front teats and the mutual distance between therear teats. Moreover, as is disclosed in FIG. 6, the mutual distance cbetween the front inlet passages 8' is longer than the correspondingdistance d between the rear inlet passages 9'.

The upper portion 2 comprises a radially projecting flange 13 and theintermediate portion 3 comprises a corresponding radially projectingflange 14. The upper portion 2 and the intermediate portion 3 are kepttogether by means of a locking member, which in the example disclosed inFIG. 1-3 is formed by a profiled clamp 15.

The profiled clamp 15 comprises two opposing obliquely upwardly andobliquely downwardly, respectively, directed flanges 15a and 15b whichabut corresponding oblique surfaces of the radially projecting flanges13 and 14, respectively. When the profiled clamp 15 is compressed bymeans of a screw member 16 disclosed in the example, the flanges 13 and14 will be pressed against each other. In order to seal the inner spaceof the housing 1, a sealing ring 17 may be provided between the radiallyprojecting flanges 13 and 14. In the example disclosed the radiallyprojecting flange 14 comprises a recess 18 extending therearound, inwhich the sealing ring 17 is provided, and the radially projectingflange 13 comprises a recess 19 having a diameter corresponding to theouter diameter of the sealing ring 17.

Furthermore, in the inner space of the housing 1 a suction pipe 20 isprovided. This extends in the direction of the center axis 5 and is bymeans of support members 21 provided at a distance from a bottom of thehousing 1. In the upper end the suction pipe 20 abuts the inner wall ofthe intermediate portion 3 and in this way the suction pipe 20 isfixedly provided in the inner space of the housing 1. Furthermore, thesuction pipe 20 may, as is disclosed in FIG. 1, comprise four wings 22which extend in a respective radial plane and are provided by a mutualangle distance of about 90° and in such a manner that a wing 22 extendsradially outwardly between each of the inlet members.

As is disclosed in FIG. 1 the claw may comprise a closing valve 23provided in the upper portion 2 and displaceable along the center axis5. The closing valve 23 is intended to close off automatically theoutlet member as the claw is attached to an animal. Furthermore, theclaw may comprise a suspension member 24, see FIG. 1.

As is disclosed in FIG. 4, the claw comprises two distributing members25 provided on the upper portion 2. Each distributing member 25comprises an inlet pipe 26 having a respective longitudinal axis 27. Theaxes 27 are provided in parallel to the longitudinal axis 7 of theoutlet nipple 6. Furthermore, each distributing member 25 comprises twoinlet pipes 28 which, via a respective short pulse conduit (notdisclosed), are connected to a pulsating chamber of a teatcup (notdisclosed). Each distributing member 25 is attached to two supportmembers 29 provided on the upper portion 2 in such a manner that thedistributing members 25 are rotatable about their respectivelongitudinal axis 27.

The claw disclosed in FIG. 5 comprises no profiled clamp but is kepttogether by means of a bolt 30 extending along the centre axis 5 throughthe whole claw. The bolt 30 comprises a step 31 abutting the upperportion 2 and in its lower end a thread on which a nut 32 is screwed. Bytightening the nut 32, the three portions 2,3 and 4 are compressedagainst each other and the upper portion 2 may be locked in an arbitraryrotational position in relation to the intermediate portion 3. The bolt30 may in its upper end be provided with a suspension member notdisclosed.

It should also be noted that the claw does not need to have a circularshape seen from above, but may for example be a quadrangle tapering in arearward direction, i.e. the front edge side is longer than the rearedge side. Such a shape is adapted to the positions in which the inletmembers are located.

By a claw, which is adapted to the position of the teats of the animalto be milked, i.e. which has a pronounced front and rear end, it may beadvantageous with four essentially fixed rotational positions for theupper portion 2, comprising the outlet nipple 6, in relation to theintermediate portion 3. These essentially fixed or marked rotationalpositions are located at a distance of about 90° from each other andcorrespond to the case that the milking machine is located essentiallyin front of, laterally of or behind the animal to be milked.

During use the claw 1 disclosed functions in the following way, see FIG.1-9. Milk from the teatcups not disclosed is sucked via the inletmembers (inlet passages 8, 9 and inlet passages 8', 9', respectively)into the inner space of the housing 1. From there, the milk is suckedfurther via the suction pipe 20 out through the outlet nipple 6 whichvia a milk conduit 33 may be connected to a collecting container of amilking machine 34. The milking conduit 33 extends in parallel to twopulse conduits (not disclosed) connecting the inlet pipe 26 of thedistributing members 25 to a vacuum pump of the milking machine (notdisclosed). The milk conduit 33 and the pulse conduits may be connectedto a conduit package. This conduit package is necessarily relativelyrigid and heavy and will therefore apply significant torsional forces tothe claw. By the claw disclosed, these torsional forces may be minimizedby a rotation of the upper portion 2 about the center axis 5 in relationto the intermediate portion 3. Preferably, the upper portion 2 isrotated so much that the outlet nipple 6 will be directed essentially inthe direction in which the milk conduit 33 and the pulse conduitsextend. This direction is defined by the disposition in a milking stallin which the claw is used. When this best direction has been chosen theupper portion 2 is locked in relation to the intermediate portion 3 bytightening the nut 32 or the screw member 16 thereby compressing theradially projecting flanges 13 and 14 of the profiled clamp 13 againsteach other.

As is disclosed in FIG. 8 and 9 the claw will, due to the configurationaccording to the invention, be suspended horizontally, i.e. the centeraxis 5 will be vertical. Because of this, the pulling force actingdownwardly at each teat will be essentially equal and thereby a uniformand equal milk extraction from each teat is ensured. Furthermore, thehorizontal position means that the milk collected in the claw may betransported away therefrom in an uniform and continuous flow, therebyreducing the risk for so called impact and backflow.

The invention is not limited to the embodiments disclosed but may bevaried within the scope of the features defined in the following claims.For instance, the outlet nipple 6 and the upper portion 2 may also berotated in a vertical direction in relation to the intermediate portion3 in order to compensate for a possible height difference between theclaw and the milking machine or due to the downwardly rotating forceapplied to the claw by the milk conduit due to its weight.

We claim:
 1. A claw for a milking machine comprising:a housing havingfour inlet members, which are adapted to connect the housing to fourrespective teats of an animal to be milked via four teatcup liners, andan outlet member, which is adapted to connect the housing to a milkcollecting member of the milking machine via a conduit member, saidhousing having a center axis extending through the claw essentiallyvertically when the claw, in an operating position, is attached to theudder of the animal, said four inlet members being distributed aroundthe center axis and provided in pairs in such a manner that they areadapted to the natural position of the teats of the udder of the animal,a first pair of the inlet members, which is intended for two front teatsof the animal, being directed obliquely forwardly and outwardly andhaving a different position with respect to the center axis than asecond pair of the inlet members, which is intended for the rear teatsof the animal and is directed obliquely rearwardly and outwardly withrespect to the center axis, wherein each inlet member comprises apassage extending through the wall of the housing, said passage beingarranged to receive one of said teatcup liners therethrough, whereineach passage is surrounded by and extends through a respective portionof the wall of the housing, wherein each passage extends in a directionwhich essentially forms a normal to said respective wall portion, andwherein this portion has essentially plane parallel surfaces on innerand outer surfaces thereof.
 2. A claw according to claim 1, wherein theinlet members are provided in pairs in such a manner that the first pairis located at a higher position with respect to the center axis a pointon than the second pair.
 3. A claw according to claim 1, wherein theinlet members are provided in pairs in such a manner that the distancebetween the inlet members of the first pair is longer than thecorresponding distance of the second pair.
 4. A claw according to claim1, wherein the inlet members are provided in pairs in such a manner thatthe passages of the first pair extend obliquely forwardly and outwardlyby a first angle in relation to a horizontal plane to which the centeraxis forms the normal, and that the passages of the second pair extendobliquely rearwardly and outwardly by a second angle in relation to thehorizontal plane.
 5. A claw according to claim 1, wherein each inletmember extends in a direction directed essentially straight towards theteat associated with the inlet member when the claw, in an operatingposition, is attached to the udder of the animal.
 6. A claw according toclaim 1, wherein the housing comprises a first portion and a secondportion wherein the outlet member is provided on the first portion,wherein the inlet members are provided on the second portion, andwherein the first portion is rotatable in relation to the secondportion.
 7. A claw according to claim 6, wherein the first portion iscontinuously rotatable in relation to the second portion to such anextent that essentially no torsional force will be applied to the clawvia the conduit member in said operating position.
 8. A claw accordingto claim 6, wherein the second portion is located beneath the firstportion in said operating position.
 9. A claw according to claim 6,including a locking member by means of which the first portion islockable in said position in relation to the second portion.